Dental simulator

ABSTRACT

The simulator includes an upper and lower facebow for mounting on a patient to record and later reproduce the three dimensional movements of the patient&#39;s mandible. The upper frame has two receptacles mounted thereon having a bore opening toward the anterior portion of the facebow. A molding material is disposed within the receptacles and the lower frame has two styli projecting into the receptacles for indenting the molding material to make an innerocclusal record during the movement of the patient&#39;s mandible. The frames are then removed and dental casts are affixed to the frames. The innerocclusal record formed in the molding material is used to reproduce all of the patient&#39;s mandibular movements.

This is a continuation of Ser. No. 176,198, filed Aug. 7, 1980, U.S.Pat. No. 4,368,041, Jan. 11, 1983.

TECHNICAL FIELD

This invention relates to dental articulators or relators, and moreparticularly to apparatus for recording and simulating the movement ofthe jaws of a dental patient for evaluation, diagnosis, and treatment ofocclusal problems and for dental rehabilitation.

BACKGROUND OF THE ART

Function, aesthetics, and comfort are prime objects of restorativedentistry, and the ability to treat occlusal problems is directlyrelated to the ability to capture and transfer jaw motion to therestoration. Existing conditions of the patient must be analyzed bymeans of a functional method and the mere relation of the teeth to eachother is not enough. Unless the relationship satisfies the functionalrequirements of the whole mouth, it may become a destructive function,creating a metabolic demand in excess of the normal requirements of themouth.

To achieve these objectives, and to prevent trauma, wear and loss ofcentric relation contacts, the cuspal elements must be free to travel inand out of centric relation closure and free to perform their functionswithout interference or lateral stresses. The height, position, andrelation of the cuspal elements are determined by studying thedeterminants of occlusion, namely, ridge and groove directiondeterminants (axis-orbital horizontal plane), cusp height and fossaedepth determinants (sagittal plane), and determinants of the lingualconcavity of upper anterior teeth. Since the length or height of thecusps is influenced by the condyle path, and the position and form ofthe cusps are determined by the Bennett movement which must harmonizewith the lateral shift, it is necessary to observe the interferencesbetween centric relation and centric occlusion position and the cusppathways during eccentric mandibular movements to determine theformation of corrective measures. See Evaluation, Diagnosis, andTreatment of Occulusal Problems by Peter E. Dawson (1974) and VolumeOne: Mouth Rehabilitation Clinical and Laboratory Procedures by MaxKornfeld (2d Ed. 1974).

Because the musculature motivates the movement of the mandible and thetemporomandibular joint determines the movements, the determinants ofthe mandibular movements that dictate the occlusal morphology must beobtained and reproduced correctly to properly treat abnormal occlusion.Unless these varieties of motions can be accurately recorded andreproduced through laboratory registrations of the study casts of theteeth, occlusal corrections may become necessary.

Laboratory duplication includes making study casts of the maxillary andmanibular teeth. Registrations are taken of the jaw movements of thepatient by one instrument and are later transferred to a secondinstrument. The casts are them mounted to the second instrument to thecorrect axis and the second instrument is used to simulate the movementsof the patient's jaws in the laboratory to permit the review of theocclusal relationships of the patient's teeth. Various prior artinstruments have been used to record and attempt to duplicate jawmovement including the pantograph, stereographic instruments,articulators, and relators.

The pantograph graphically records the various positions and movementsof the mandible and then the resulting graphs are utilized to adjust anarticulator which attempts to reproduce the paths of the patient'smovements. The pantograph relies upon the hinge axis even though thehinge axis has control only along the border paths when we masticate.The pantograph has two facebows with six recording slides and six stylithat scribe the paths of the centers of rotation of the mandible. Thehinge axis if first located, and then an innerocclusal record is takenat centric relation or centric occlusion. The pantograph thengraphically records the movements of the jaw. In making these records,the clutches mounted to the pantograph have to be separated verticallyso that there will be no tooth guidance during the registrations, and atthe same time separated a minimum distance to reduce the error. After arecord of the jaw movements has been registered and the orbital guideset, the arms of the pantograph are locked together and the entireassembly is removed intact from the patient and is transferred to themounting frame or jig that holds the facebow in proper relation to theadjustable articular while the attaching stone sets.

There are two types of articulators, the semiadjustable articulator andthe adjustable articular. The semiadjustable articulator is oftenreferred to as the checkbite articulator which reproduces the horizontalcondyle paths from an innerocclusal record made at centric relation anda bite record made in the protrusive position. The resultant path is astraight line between the two points. Lateral pathways are set from thecentric bite record (innerocclusal record) and records are made in theleft lateral and right lateral jaw positions. The semiadjustableinstrument can accurately record the hinge axis but cannot record thefull range of lateral and protrusive condylar movements. Further,semiadjustable instruments do not precisely record the Bennett shift.With adjustable articulators, a more complete preoperative occlusalanalysis is possible than is possible with semiadjustable articulators.The improvement in accuracy is the difference between straight line vs.curve pathways plus the differences of timing of the Bennett shift.

A stereographic instrument may be used in place of the pantograph fortaking registrations which are subsequently transferred to anotherinstrument such as the TMJ Articulator or the Gnathic Relator. Thestereographic instrument generally includes upper and lower intraoralclutches having a central bearing point therebetween. An innerocclusalrecord is made in centric relation or centric occlusion. Recordings arethen made by indenting three or four points, mounted on one clutch, intodoughy self-curing acrylic on the surface of the opposite clutch andthen moving the mandible. When the stereographic record is completed,the acrylic guide paths are allowed to set hard. In using the TMJArticulator, the stereographic clutches are mounted on the TMJArticulator using the centric bit record (innerocclusal record). Adoughy mixture of TMJ acrylic is placed in plastic receptacles at thecondyles and the condyles are guided by moving the points through thepaths made by the indentations. After the condyle paths are recorded,the casts are mounted in place of the clutches. The Gnathic Relator is adevice that uses the stereographic clutches after anterior guidance hasbeen corrected in the mouth. The clutches are screwed into the studycasts thereby permitting the border pathways to be reproduced by handusing the handheld models. Further description of the above is found inEvaluation, Diagnosis, and Treatment of Occulusal Problems, by Peter E.Dawson (1974) at pages 124-131 and is incorporated herein by reference.

Many practical problems have been encountered using such prior arttechniques and instruments. Pantographic tracings are not more accuratethan the paths of movement that the operator records. Many pantographicerroes result from failure to achieve a true terminal hinge condyleposition during any part of the tracing. Further, there is the fear ofrecording a protrusive lateral path instead of the straight lateralborder path.

Another disadvantage of pantographic devices is that the tracings mustbe made at a considerably opened vertical dimension to make room for theclutches. It is essential that the terminal hinge axis be recordedprecisely or the incorrect axis of the closure will introduce errors. Itis also probable that in some mouths, at least, the border movements aredifferent at the opened position from what they are at the correctvertical position.

Errors in mounting of pantographic devices are common and easy to make.The slightest movement of either clutch produces a magnified error atthe tracing plate. Studies have shown that reproducibility ofpantographic tracing is seldom achieved.

One of the most important purposes of an articulator is to relate theupper and lower models to the correct horizontal axis. Semiadjustablearticulators do not permit a correct relationship to the axis ofclosure. Sizeable errors are introduced into all aspects of occlusalform when incorrect horizontal and vertical axes are not used. Theproblem with simple hinged type articulators is that the only movementsthat they can make are movements the patient cannot make.

Tooth relations on the articulator will not be the same as in the mouthunless the opening-closing hinge in centric relations are the same onthe articulator as in the patient's mouth. The articulator mustreproduce the same relation of the casts to the axis of the instrumentthat the teeth have to the axis of the manible. Unless the casts can beoccluded by closing them on the same arc of closure as that exhibited bythe patient, erroneous conclusions may be drawn concerning existingpatterns and the need for restorative procedures for the patient.

The stereographic instrument requires intraoral clutches which must befitted inside of the patient's mouth. The central bearing point must beproperly sized or the vertical dimension may be in error. No recordingsare made other than in the closed position since an open position willcause the pointers to lift from the acrylic. Further, if the intraoralclutches are not mounted in the mouth in the same position as on thestudy casts, error will be introduced.

Both the pantographic devices and stereographic instruments require aninnerocclusal record made in centric relation or centric occlusion. Suchan innerocclusal record is required to accurately orient and relate themaxillary and mandibular casts on the articulator. Unless the casts areproperly oriented, upper to lower, on the articular, the recordingscannot be properly reproduced. It has been found to be difficult toobtain an accurate bite in centric relation or centric occlusion.

Transfer is also required using the stereographic instrument. The TMJarticulator relies upon the accurate transfer of the registrations ofthe stereographic instrument. Any time such a transfer is made andrecordings have to be duplicated, errors arise.

A great amount of time is often wasted on procedures that have little orno value in specific cases. The articulator should be used to achieveprecise reproduction of condylar pathways and not become subservient tothe particular techniques such as the transfer of the recordings to aduplicator of the jaw movements.

Mandibular movements are three-dimensional in character and have beenfound to be complex. The envelope of motion has anterior, posterior, andlateral limits, and there is a sequence of motion from one position tothe other. Not only do the joints rotate in the vertical, horizontal,and sagittal planes, but they are capable of bodily side shift (theBennett movement) which adds another motion to the complexity ofmovement. When rotation and translation are combined, there is noconstant axis of control. The axis that changes is called theinstantaneous axis of rotation, and it is only in control for an instantand can only be located when motion is stopped. If the instantaneouscenters cannot be located, there is no way of plotting the functionalenvelope of motion and the border paths of the complete envelope must beused. The task of duplicating such mandibular movements has been foundto be lacking in prior art devices.

The present invention overcomes the deficiencies of pantographs,stereographic instruments, articulators and relators by eliminating thenecessity of an innerocclusal record at centric relation or centricocclusion and by eliminating the transfer of the recordings to amechanical duplicator of the movements of the jaw. Further, the presentinvention provides a three-dimensional recording which is morerepeatable and readable than those that exist in the prior art. Thepresent invention becomes a substitute for the jaws in which allocclusal determinants and the opening and closing axis relations areprecisely incorporated. The present invention does not require thelocation of the hinge axis or the establishment of the axis-orbitalplane or centric relation. No interpolation is required in itsrecordings and duplication of jaw movement. The present inventionpermits reproduction of the patient's mandibular movements, accuraterecord and check of centric relation, alteration of the verticaldimension with certainity, recordation of the limit of the maximalocclusal opening, minimization of the adjustment in the mouth duringrestoration, and duplication of all arcs of closure. Other objects andadvantages of the present invention will become apparent from thefollowing description.

DISCLOSURE OF THE INVENTION

The present invention includes a maxillary and mandibulary facebow, amaxillary and mandibular support and an incisal pin. Receptacles aremounted on the ends of the side arms of the maxillary facebow, and theside arms of the mandibular facebow have styli disposed thereonprojecting into the receptacles of the maxillary facebow. Means arelocated at the mid-point of both the facebows for the attachment oflabial cores and/or bite rims.

The labial cores are formed on study models of self-polymerizing acrylicand are lined with a soft rubber base material for comfort is used asfacial cores. These are constructed such that there will be nointerference with the movement of the mandible. These cores are on themaxillary and mandibular facebows, respectively, and have mountingscrews for attachment to their respective facebows placed at slightlyconverging angles. This separates the facebows to prevent interferenceposteriorly. At this stage the patient has the cores and facebowspositioned such that the mandible stylus is positioned in the center ofthe maxillary receptacle. This is further centered and adjusted by meansof adjustment screws on the upper receptacle. Self-polymerizing plasticis placed in the maxillary receptacles and the patient is instructed toopen wide, protrude right and left, lateral excursions and retrude themandible in repeated movements until the plastic is rigid. At this pointan innerocclusal record at any position is taken using wax, acrylic,zinc oxide eugenal plaster or any other suitable material.

The completed apparatus is removed. Master casts, study casts, orworking casts can now be positioned in the occlusal records. Themaxillary and mandibular supports with mounting rings are attached tothe maxillary and mandibular facebows by means of connector screws.These are screwed in position on both sides and the incisal pin ispositioned. The casts are mounted by plastering both the upper and lowerin place. The anterior sections of the maxillary and mandibular facebowswith the facial cores or bite rims are removed by means of disconnectscrews. The remaining apparatus becomes the working articulator. Notransfer to another instrument is necessary. The movements of which areexact duplications of the patient's mandible. Additional working modelscan be added to the instrument by removing the prior models are usingthe innerocclusal record to position the new models.

BRIEF DESCRIPTION OF THE DRAWINGS

For a detailed description of a preferred embodiment of the invention,reference will now be made to the accompanying drawings wherein:

FIG. 1 is an exploded view of the dental simulator of the presentinvention;

FIGS. 2A, 2B, and 2C are plan, elevation, and side views, respectively,of the maxillary facebow shown in FIG. 1;

FIG. 3 is a section view of the maxillary facebow of FIG. 2B taken atplane 3--3 in FIG. 2B;

FIGS. 4A, 4B, and 4C are plan, elevation, and side views, respectively,of the mandibular facebow shown in FIG. 1;

FIGS. 5A, 5B, and 5C are plan, elevation and side views, respectively,of the maxillary support shown in FIG. 1;

FIGS. 6A, 6B, and 6C are plan, elevation, and side views, respectively,of the mandibular support shown in FIG. 1;

FIG. 7 is a prospective view of the maxillary and mandibular facebows inplace on a patient; and

FIG. 8 is a prospective view of the stone casts mounted on the maxillaryand mandibular support arches in position with the maxillary andmandibular facebows having been removed.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring initially to FIG. 1, there is illustrated the simulator of thepresent invention shown in an exploded view. The simulator includesmaxillary and mandibular facebows 10, 12, maxillary and mandibularsupports 14, 16, and incisal pin 18.

Referring now to FIGS. 2A, 2B, and 2C, maxillary facebow 10 includes across-bar 20 and two side arms 22, 24. Receptacles or mold cups 26, 28are mounted on one end of each of the side arms 22, 24, respectively.Side arms 22, 24 include vertical guide pins 42, 44, respectively,located by approximately their mid-portion for the alignment of uppersupport 14 as hereinafter described. Dove-tailed slots 30, 32 withsquare seats are disposed in the slotted ends of side arms 22, 24opposite receptacles 26, 28 for matingly engaging opposing dove-tailedprotrusions 34, 36 on the ends of cross-bar 20. Lock screws 38 attachside arms 22, 24 to each end of cross-bar 20 at dove-tailed slots 30,32.

Referring again to FIG. 1, receptacles 26, 28 are mounted on side arms22, 24 by means of brackets 150 secured to the ends of side arms 22, 24.Means are provided to permit both vertical and horizontal adjustment ofreceptacles 26, 28 on brackets 150. Brackets 150 include a verticalgroove 152 which has a vertical slot 154. An adjustment plate 156 has avertical projection 158 and a horizontal projection 160. Verticalprojection 158 is slidingly received within vertical groove 152.Receptacle 26 has a T-shaped horizontal channel 170 on its back side forreceiving bar 162 and horizontal projection 160. A bolt 164 is affixedto bar 162 and passes through an aperture 166 in plate 156 and throughslot 154. Nut 168 is threaded onto bolt 164 to mount receptacle 26 tobracket 150. By loosening nut 168, projection 158 is permitted to slidein groove 152 for the vertical adjustment of receptacle 26 andprojection 160 is permitted to slide in channel 170 for horizontaladjustment. Receptacle 28 is adjustably mounted on a like bracketdisposed on side arm 24.

Referring now to FIGS. 2 and 3, cross-bar 20 includes a series of holes40 at its mid-point for receiving holder nut and screw 42 for attachinglabial core 44. The axes of holes 40 are slanted at a downward angle tothe plane of the surface of cross-bar 20. Such downward slant positionsthe labial core 44 in proper position for engagement with the patient'steeth. Cross-bar 20 is ground down to form a plane 46, at the entranceand exit of holes 40, which are perpendicular to the axis of the holes40.

Referring now to FIGS. 4A, 4B, and 4C, mandibular facebow 12 is similarin construction to that of maxillary facebow 10. Mandibular facebow 12includes two side arms 52, 54 attached to cross-bar 50 by lock screws 56passing through dovetailed slots 58, 60. Side arms 52, 54 also includevertical guide pins 76, 78, respectively, at approximately theirmidportion for alignment for mandibular support 16 as hereinafterdescribed. Support arms 68, 70 are mounted on the ends of side arms 52,54, respectively, and include apertures for receiving studs or styli 72.Styli 72 are rounded for making impressions in the acrylic to be placedin mold cups 26, 28 as hereinafter described. Adjustment screws 74 arethreadingly mounted in support arms 68, 70 for adjusting the protrusionof styli 72 into mold cups 26, 28.

Cross-bar 50, like cross-bar 20, also includes a series of holes 64 atits mid-point for receiving holder nut and screw 62 for attaching labialcore 66. The axes of holes 64 are slanted upward to the plane of thesurface of cross-bar 50 in the same manner as holes 40 are slanteddownward in cross-bar 20. Thus, the axes of holes 40 and 64 convergetowards the patient's mouth.

Referring now to FIGS. 5A, 5B, and 5C, maxillary support 14 formaxillary facebow 10 includes end brackets 100, 102 supporting arch 104.Mounting screws such as at 106 affix the ends of upper support arch 104to brackets 100, 102. A maxillary plate 108 is mounted on bracket 110which in turn is disposed at the mid-point of upper support arch 104 byan appropriate fastening means such as by screws 112. Maxillary plate108 includes a plurality of holes 111 for affixing plaster 113 andmaxillary study cast 115. Bracket 110 includes an adjustment screw 114threadingly engaging therewith at bore 116 for adjusting the verticalposition of incisal pin 18. Pin 18 includes a vertical guide channel 118for receiving screw 114.

Referring now to FIGS. 6A, 6B, and 6C, mandibular support 16 ofmadibular facebow 12 includes a lower support arch 120 mounted on endbrackets 122, 124. The ends 88, 90 of lower support arch 120 arefastened to brackets 122, 124 by screws 126. Mandibular support 16further includes a mandibular plate 130 affixed to the mid-portion oflower support arch 120 by bracket 132. Mandibular plate 130 includes aplurality of holes such as at 136 to hold the plaster 140 on themandibular study cast 142. The extreme end 138 of mandibular plate 130is dimensioned to engage and support the lower end of incisal pin 18.Through the use of adjustment screw 114, the distance between maxillaryplate 108 and mandibular plate 130 may be adjusted.

In operation, study casts 115, 142 of the patient's mouth are made bytaking impressions using an elastic impression material such asalginate, hydrocolloid, silicon, or rubber base, and the study casts115, 142 are each made by pouring into the elastic impression a hardartificial stone. Preoperative casts 115, 142 are used for the study ofocclusal relations for diagnosis, treatment planning, and method andtype of therapy. Labial cores 44, 66 are constructed for recording themovement of the mandibular.

As shown in FIG. 7, the maxillary and mandibular facebows 10, 12 aremounted on the patient to record the movement of the mandibular. Labialcores 44, 66 are mounted on the maxillary and mandibular facial surfacefor attachment to maxillary and mandibular facebows 10, 12.

In positioning the facebows 10, 12 on a patient, the styli 72 andreceptacles 26, 28 are placed above the occlusal plane (the plane alongwhich the teeth meet during closure) and anterior to thetemporomandibular joint. Such positioning insures that the axis ofrotation of styli 72 in receptacles 26, 28 will cause the tip of styli72 to move anteriorly from centric relation as the patient opens hismouth. Although the present invention would operate even though thefacebows 10, 12 were located other than in the preferred position, thestyli 72 could move back and/or down within receptacles 26, 28preventing the centric relation record from being the deepest impressionwithin the plastic of the receptacles 26, 28. However, as has beenindicated, the innerocclusal record need not be centric relation orcentric occlusion since the present invention will function using aninnerocclusal record taken at any position. Means may be provided on thefacebow 10 for supporting the facebow 10 on the patient. Such meanscould include ear plugs mounted on facebow 10 which fit within the ear.

Receptacles 26, 28 are filled with a self-polymerizing plastic and styli72 mounted on side arms 52, 54 of mandibular facebow 12 are insertedinto the plastic of the receptacles. An innerocclusal record is taken atany position to establish a base position of the maxillary andmandibular teeth for later properly relating the upper cast 115 to thelower cast 142. The patient then makes various movements with the jawand the styli 72 form multiple imprints in the plastic within thereceptacles 26, 28.

Referring now to FIG. 8, the upper and lower stone casts 115, 142 of thepatient's teeth are then mounted on labial cores 44, 46 respectively.Maxillary and mandibular supports 14, 16 are mounted on facebows 10, 12respectively, aligned thereto by guide pins 42, 76, and affixed theretoby mounting screws 144, 146. The upper and lower stone casts 115, 142are properly oriented and related to each other using the innerocclusalrecord and are then plastered into place onto maxillary plate 108 andmandibular plate 130 with the holes 111, 136 in those plates holding theplaster 113, 140 thereto.

The vertical incisal pin 18 is mounted and set within bore 116 ofbracket 110 and in engagement with mandibular plate end 138. Cross-bars20, 50 of maxillary and mandibular facebows 10, 12 are then removed.Vertical pin 18 stabilizes the movement of the simulator. A vertical pincan be positioned on the occlusal table for customizing a plasticincisal guidance.

The imprint of the styli 72 in the plastic permits the duplication ofjaw movement by stone casts 115, 142 including the terminal horizontalaxis of condylar rotation, the vertical axis of condylar rotation, thesagittal axis of condylar rotation, the simultaneous multiple axes ofrotation during condylar translations, the straight protrusive pathwaysof each condyle, the pathways of each condyle during straight lateralexcursions of the mandible, and the multiple pathways of each condyleduring all possible excursions of the mandible between straight lateraland straight protrusion.

Further, the action of the mandible is captured in its movement in thethree horizontal, vertical, and sagittal planes and the movements causedby rotation about three different centers-horizontal (transverse axis),vertical, and sagittal. Although during function the movement of theseplanes and rotation about these centers occur simultaneously, thepresent invention does not require their precise location orregistration since they are automatically reproduced during the movementof the mandibular facebow 12 within the imprints. No registrations needbe transferred and the present invention does not require a centricrelation record or centric occlusion record or registration since theyare automatically reproduced during the movement of mandibulary facebow12 within the imprints of the plastic. No registrations need betransferred to a mechanical counterpart, such as an articulator, whosemandibular member is so constructed that it is also supposed to move inthose same three planes with rotation about those same three centers.

The present simulator is sturdy and exact in construction, is simple butefficient in mechanics of operation, and is capable of maintainingconstant in duplicating desired movements.

Thus, the purpose of the simulator is achieved by reproducingeffectively the mandibular movements of a patient at the laboratorybench. Because of its accuracy in the simulation of the jaw movement,the result is a better fabricated prosthesis. Further, such accuracy ofsimulation allows for more accurate occlusal relationships in therestorations and only requires minor adjustments after installation. Itis believed that the present invention achieves maximum balancingbetween obtaining proper restoration within reasonable limits of timeconsumption and reasonable expertise and quality of results.

One of the important basic objectives is that patients must have thecapability of reaching their maximum closure comfortably from manypositions of the mandible without tooth interference. It is believedthat in the use of the present invention reflective or interceptiveocclusal contact can be prevented in the centric positions to avoiduncontrolled triggering of parafunctional or peridontal insult. Theultimate objective, of course, is to prevent faulty functional movementsthat result in restorations which cause peridontal breakdown of theremaining teeth, temporomandibular joint disorders, or muscle spasm.

While a preferred embodiment of the invention has been shown anddescribed, modifications thereof can be made by one skilled in the artwithout departing from the spirit of the invention.

What is claimed is:
 1. A dental apparatus for mounting on the facialsurfaces of the maxilla and mandible of a patient to record themovements of the patient's mandible comprising:a first frame having twosubstantially horizontal receptacles having means for mounting adjacentto the patient's head above the occlusal plane formed by the meeting ofthe maxilla and mandible during closure and anterior to thetemporomandibula joint, said first frame having an anterior portionhaving means for mounting on the facial surfaces of the maxilla andmandible, said receptacles having an opening toward said anteriorportion; a molding material disposed in said receptacles; a second framehaving two substantially horizontal styli disposed thereon having aportion thereof projecting into said receptacles in a directionextending posteriorly of said anterior portion, said styli indenting themolding material during movement of said second frame with the mandiblein the horizontal, vertical and sagittal planes for recording threedimensional jaw movement, said portions of said styli received withinsaid receptacles moving anteriorly within said receptacles as thepatient opens the mouth and posteriorly as the patient closes the mouth.2. The dental apparatus of claim 1 wherein said first and second framesare U-shaped members having side portions adapted for positioningadjacent the sides of the patient's head and a front portion formounting on the facial surfaces of the maxilla and mandible; saidreceptacles having a bore for housing said molding material; the axis ofsaid bores and said styli being parallel to said side portions.
 3. Adental apparatus for mounting on the facial surfaces of the maxilla andmandible of the patent to record and then to reproduce the threedimensional movements of the mandible, comprising:a first frame havingtwo receptacles mounted thereon, said first frame having means forpositioning said receptacles adjacent to the sides of the patient's headand an anterior portion having means for mounting on the facial surfacesof the maxilla and mandible of the patient, said receptacles openingtoward said antieror portion; a molding material disposed in saidreceptacles; a second frame having two styli disposed therein, saidstyli projecting into said receptacles in a direction extendingposteriorly of said anterior portion and forming indentations in saidmolding material during the three dimensional movement of the patient'smandible to make an innerocclusal record; and means for reproducingthree dimensional movements of the patient's mandible, includingmeansremovably mounted on said first and second frames for attaching casts ofthe patient's maxilla and mandible to said first and second frames, andmeans for restricting the position of the mandible cast relative to themaxilla cast, said restricting means including said styli and saidreceptacles, with said styli projecting into said indentations in saidmolding material within said receptacles and into contact with saidmolding material, said molding material having hardened since beingindented by movement of the patient's mandible, the mandible cast beingfree to move except as prevented by said restricting means.
 4. A dentalapparatus for recording and then reproducing the three dimensionalmovements of the mandible, comprising:an upper stationary frame havingan anterior portion adapted for mounting on the patient's jaw and onlytwo receptacles mounted thereon, said receptacles being adapted forpositioning adjacent each side of the patient's head and having anopening facing towards said anterior portion, said receptacles beingadapted to hold a molding material; a lower movable frame having ananterior portion and two styli disposed thereon, said styli projectingposteriorly into said receptacles for indenting the molding materialduring the three dimensional movement of the patient's mandible, saidstyli being the only contact with said upper stationary frame during therecording of the three dimensional movements; means removably mounted onsaid anterior portions of said upper and lower frames for attachment tothe facial surfaces of the patient's maxilla and mandible, respectively,said lower movable frame being moved with respect to said upperstationary frame by the patient's mandible in all three dimensionalmovements in the horizontal, vertical, and sagittal planes including allarcs of closure; means removably mounted in said upper and lower framesfor attaching casts of the patient's maxilla and mandible to said upperand lower frames; and said styli indentations and styli reproducing allof the three dimensional movements of the patient's mandible with thecasts attached to said upper and lower frames.
 5. A method of recordingand duplicating the jaw movements of a patient comprising:mountinglabial cores on a maxillary facebow and on a mandibular facebow;inserting the patient's head into the maxillary facebow and mandibularfacebow; affixing the labial cores to the maxilla and mandible of thepatient; positioning a substantially horizontal stylus, mounted on eachside of the mandibular facebow, into adjacent substantially horizontalreceptacles mounted on each side of the maxillary facebow; adjusting thehorizontal styli within the receptacles; placing self-polymerizingacrylic in the receptacles; moving the patient's mandible threedimensionally in the horizontal, vertical, and sagittal planes for allpositions of the mandible; indenting the acrylic by the styli as thepatient moves the jaw three dimensionally; taking an innerocclusalrecord in any position; removing the facebows from the patient's head;preparing dental casts; mounting maxillary and mandibular arches to themaxillary and mandibular facebows; plastering the dental casts to themaxillary and mandibular arches; and moving the dental casts within thelimits required by the styli within the indentations of the acrylic toduplicate the three dimensional movement of the patient's jaw.